Electronic Bevel Jig

ABSTRACT

Programmable bevel jig which is simple to use and can easily be attached to a workpiece to produce various types of complex bevels. Multiple angles and angle tolerances can be programmed into the jig, and then selected during machining. Different color LEDs indicate position of the jig with respect to a selected bevel angle, and also what pre-programmed bevel angle is selected. The reference angle of the jig is programmed into the jig by placing the jig on the grinding tool and pressing a pushbutton switch.

BACKGROUND

This invention relates to an electronic bevel jig which can be used with a tool such as a grinder or cutter to machine a workpiece to create various types of bevels.

Knives, swords, axes, and scissors are examples of objects in which bevels are ground. To produce a cutting edge on a knife, metal must be removed using a belt grinder at an angle. This angle is called the bevel angle. FIG. 1 shows the bevel angle in a cross sectional view of a knife blade. There are several grind types which use various bevel angles. Flat grind, hollow grind, sabre grind, compound grind, and convex grind are some of the types used on knives. Almost all grind types require multiple bevel angles to remove metal and finally to produce a cutting edge.

There are several types of mechanical bevel jigs used by knife makers and machinists. Almost all these jigs are homemade. Some set the bevel angle by adjusting a bolt which protrudes from the bottom of an L-shaped bracket. The knife is mounted on the vertical part of the bracket using a clamp. This type of mechanical jig requires some type of inclinometer or some other means to set the bevel angle by adjusting the height of the bolt that is sticking out of the bottom of the L bracket. To grind both sides of the knife blade, the knife must be removed from the clamp several times during the machining process. These types of mechanical jigs are very bulky and require large work plates on the grinder. Also, adjustment of the bolt becomes tedious when creating compound bevels. There is another type of mechanical bevel jig (U.S. Pat. No. 798,760,882) which sets a bubble at the desired angle using an inclined piece of wood. The inclined wood is first placed on the platen of the grinding tool and the bubble is placed on the wood. The bubble is then centered by rotating the jig. The jig is then attached to the knife through a clamp. When trying to create multiple bevel angles, setting the angles using inclined pieces of woods and re-adjusting the jig becomes time consuming and tedious and in some cases impractical. This is especially true if one is trying to create a compound bevel or a near convex bevel where numerous bevel angles are required. The other problem with using the bubble to grind bevels, is the effort required to center the bubble during the grinding. The amount of effort needed, can cause eye strain, and can be very tiring. Yet one other problem with using the bubble to create bevels, is inaccuracy of the bevel. The machinist would not know how close his created bevel angle is to the actual desired angle. All these jigs, are either impractical or extremely difficult to use when multiple bevel angles are required.

SUMMARY

The present invention overcomes the above problems by providing a programmable jig that is simple to use and can easily be attached to a workpiece to produce various types of complex bevels. There are different types of bevels which are applied to knife blades, swords, axes, and other objects. FIG. 2A shows the Hollow Grind bevel which creates a concave beveled cutting edge. This type of grind produces a very sharp but weak edge. FIG. 2B shows the Flat Grind in which the blade is tapered from spine all the way to the edge of blade. FIG. 2C shows the Sabre Grind. In this type of grind, the bevel starts about the middle of the blade. This grind produces more blade strength. FIG. 2D shows the Chisel Grind in which only one side of the blade is beveled. FIG. 2E shows the Compound Grind which includes multiple bevels to improve cutting ability and strength. FIG. 2F shows the Convex Grind which produces a very strong edge. This type of grind is mainly used in axes. Except for the Hollow Grind, all the other grinds shown, can be produced by the present invention. Multiple angles and angle tolerances can be programmed into the jig, and then selected during machining, by the press of a single pushbutton switch. Different color LEDs are used in the jig to indicate position of the jig with respect to a selected bevel angle. The LEDs also indicate what pre-programmed bevel angle is selected. The reference angle of the jig is easily programmed into the jig by placing the jig on the grinding tool and pressing the pushbutton switch. The jig provides two modes of operation: 1—Individual Angles mode, and 2—Incremental Angles mode. In the Individual Angles mode, several individual angles and angle tolerances can be programmed into the jig and then selected during machining to produce flat grinds, chisel grinds, sabre grinds, and compound grinds. In the Incremental Angles mode, a starting bevel angle, an ending bevel angle, a step size, and a bevel angle tolerance are programmed into the jig. During machining, the jig automatically sets its angle to the pre-programmed starting bevel angle. The machinist machines the workpiece at that angle and then increments or decrements to the next angle which is determined by the programmed step size. The machinist machines the workpiece again and repeats the process until the programmed end bevel angle is reached. This mode can be used to produce near convex type grinds.

DRAWINGS

FIG. 1 Knife blade bevel angle.

FIG. 2A Hollow grind

FIG. 2B FLAT grind

FIG. 2C Sabre grind

FIG. 2D Chisel grind

FIG. 2E Compound grind

FIG. 2F Convex grind

FIG. 3 Block diagram of Electronic Bevel Jig

FIG. 4 Side view of Electronic Bevel Jig

FIG. 5 Setting the reference angle

FIG. 6A Two red LEDs are turned on

FIG. 6B Two red LEDs and two yellow LEDs are turned on

FIG. 6C All LEDs are turned on

FIG. 7 Setting the blade in the up position

FIG. 8 Setting the blade in the down position

FIG. 9 Turning off the Electronic Bevel Jig

FIG. 10A Screenshot of the application software, Individual Angle Mode

FIG. 10B Screenshot of the application software, Incremental Angle Mode

FIG. 11 Electronic Bevel Jig and bevel angle

FIG. 12 View of the pushbutton switch on the jig

FIG. 13 View of the USB port on the jig

FIG. 14 Jig mounted on the knife with blade in the up position

FIG. 15 Jig mounted on the knife with blade in the down position

DETAILED DESCRIPTION

FIG. 3 shows a block diagram of the preferred embodiment 10 of the present invention. The DC-DC converter 209, converts the voltage of the rechargeable battery 210, to regulated 5V DC. The DC-DC converter 209 provides power to the microcontroller 201, the buffer 213, the temperature sensor 203, the accelerometer 202, the LED drivers 206, and the Reset Generator 211. The Reset Generator circuit 211, resets the microcontroller 201 if there is a brownout on the 5V DC supply. The microcontroller 201 detects bevel angles by reading voltage outputs of the accelerometer 202. The microcontroller 201 also detects presses of pushbutton switch 11, drives LEDs 207, reads device temperature, and communicates through a USB port 19 to a Personal Computer (PC). All bevel angles and angle tolerances are programmed into the microcontroller 201 via the USB port 19. The USB port 19 is also used to charge the rechargeable battery 210 by either connecting a dedicated power supply adapter or by connecting to a PC USB port. The microcontroller 201 has internal programmable memory to store all programmed settings. FIG. 4 shows a side view of the electronic bevel device 10. FIG. 11 shows the electronic bevel device 10 and the bevel angle. FIG. 12 shows the end of jig 10 where the pushbutton switch 11 is located. FIG. 13 shows the end of jig 10 where the USB port 19 is located. LEDs 12, 13, 14, 15, and 16 provide position feedback to the user. Green LED 14 is used to show that the angle of device is within +/−0.5 of angle tolerance. Yellow LEDs 13 and 15, are used to show that the angle of the device is within +/−tolerance. Red LEDs 12 and 16, are used to show that the angle of the device is outside the programmed tolerance. The LEDs 207 are also used to show to the user that the temperature of the device is outside the specifications. All LEDs 207 flash when temperature is not within the limits. The LEDs 207 are also used to show what the current angle setting of the device is. The device has two modes of operation: 1—Individual angles, and 2—Incremental angles. The device is placed in these modes by programming via the PC and the USB port 19. When device is in Individual Angle mode, up to five individual angles and tolerances may be programmed into the device. Once the device is programmed, the user can select individual angles using the pushbutton switch 11. When the pushbutton switch 11 is pressed momentarily, the device shows the present angle setting of the device by turning on a number of LEDs. If the red LED 12 is turned on, that indicates Angle 1. If the red LED 12 and the yellow LED 13 are turned on, that indicates Angle 2. If red LED 12, yellow LED 13, and green LED 14 are turned on, that indicates Angle 3. If red LED 12, yellow LED 13, green LED 14, and yellow LED 15, are turned on, that indicates Angle 4. Finally, if all LEDs 207 are turned on, that indicates Angle 5. The user then has 3 seconds to press the button again to advance to the next angle. The pushbutton switch 11 has other functions as well. The pushbutton switch 11 is used to set the reference angle of the device. The reference angle is basically the angle of the grinder used to produce the bevel. To set the reference angle, the device is attached to the blade, and the blade is placed on the grinder's platen as shown in FIG. 5. Then the pushbutton switch 11 is pressed and held. If the button is pressed and held for more than three seconds, all LEDs 207 are then turned off. The device then detects if there is no movement or vibration. If no movement is detected, it then proceeds to set the reference angle. This action is shown by turning on the red LEDs 12 and 16 first as shown in FIG. 6A, then the yellow LEDs 13 and 15 as shown in FIG. 6B, and finally the green LED 14 as shown in FIG. 6C. Another function of the pushbutton switch 205 is to set the blade position. Some machinists prefer the blade to be up when grinding a bevel angle. Others prefer the blade to be down. FIG. 14 shows the jig 10 mounted on a knife with blade in the up position. FIG. 15 show the blade in the down position. To set the blade position up, the user must hold the device 10 vertically with the pushbutton switch 11 facing up and then press the switch momentarily as shown in FIG. 7. The device then emits a tone to indicate that the blade position is successfully programmed. Also, the blade position is shown during the grinding by pressing the button 11 momentarily while the device is held at an angle less than 60 degrees. When the button is pressed momentarily, the LEDs 207 are turned on in succession towards the grinder if the blade position is programmed to be up. To program the blade position to be down, the user must hold the device 10 vertically with the pushbutton switch 11 facing the floor as shown in FIG. 8, and then press the pushbutton switch 11 momentarily. The device again emits a tone to indicate the successful programming of the blade position. Programming of the blade position to the up position means that the bevel angle is in the positive direction with respect to the reference angle. Programming of the blade position to the down position means that the bevel angle is in the negative direction with respect to the reference angle. One other function of the pushbutton switch 11 is to turn the jig 10 on or off. To turn the jig 10 on, the user must press and hold the pushbutton switch 11 until all LEDs 207 are turned on and either one beep or two beeps are heard through the piezo transducer 214. The user can then release the button and the device then goes into normal operating mode. The number of beeps indicates to the user what mode the jig 10 is in. One beep means Mode 1 which is the Individual Angle mode and two beeps means Mode 2 which is the Incremental Angle mode. To turn the device 10 off, the user must hold the device in vertical position either with the pushbutton switch 11 facing up or down as shown in FIG. 9, and then press and hold the pushbutton switch 11 for more than three seconds. The device then turns off all LEDs 207 and emits three beeps. Once the button is released, the device 10 is then turned off. In the off mode, the device 10 goes into a deep sleep mode to conserve battery power. The Incremental Angle mode of the device consists of a starting angle, an end angle, the step angle, and the tolerance. The parameters for this mode of operation are programmed into the device via a PC and through the USB port 19. This mode can be used to generate near convex bevels. Bevels of up to 450 steps can be accomplished. When device is in this mode, on power up, the device emits two beeps. After power up, the angle of the device is automatically set to the starting angle. To advance to the next angle, the pushbutton 11 is momentarily pressed. The LEDs 207 are turned on in sequence in the direction of the grinder if blade position is up, to show advancing to the next angle. Once the end angle is reached, the device emits three beeps and goes to off mode.

Digital filtering is used to filter out unwanted noise on the accelerometer signal. The noise sources are 60 HZ from machine and lighting fixtures, RF noise from various sources, operator's unsteady hand, and the vibration from grinding machine.

Custom PC application software is used to program the modes, angles, and tolerances. FIG. 10A and 10B show screenshots of the application software. The software also shows the battery charge level and the temperature of the device.

The device is mounted on an L shaped bracket. A magnet is attached to the L bracket via two screws. The assembly then attaches to the blade by the magnet. The blade must be magnetically attractive to the magnet for the assembly to attach to the blade properly and securely. If the blade is not magnetically attractive, a magnetically attractive bracket must be attached to the blade first and then the device would attach to the bracket.

In another embodiment, a wireless module on-board enables the jig to communicate with cell phones or tablets or PCs to read the angle of device, read the programmed angles of the device, and to program new values into the jig.

In yet another embodiment, the bevel angles and tolerances are programmed into the device via speech recognition and programmed values are voiced to the user using speech synthesis.

In yet another embodiment, instead of LEDs showing the device position in relation to the programmed angle, audio is used to indicate position. Audio can either be synthesized speech or tones to indicate to the operator the position of the device.

In yet another embodiment, the angles and tolerances are programmed into the device via switches. 

1. An electronic bevel jig for positioning the angle of a workpiece with respect to a tool so that said workpiece can be machined by said tool at a predetermined angle, comprising: a. a microcontroller, b. means of measuring angle of said jig with respect to the horizontal plane or vertical plane, c. programmable memory: to store multiple individual angles and multiple angle tolerances, and to store starting, ending, and step size of range of angles, d. means of programming said angles and angle tolerances into said memory, e. means of selecting multiple angles and angle tolerances, f. means of setting the reference angle of said jig, g. means of selecting positive or negative angles with respect to said reference angle, h. means of providing feedback to a machinist indicating position of said jig with reference to a selected angle, i. means of providing warning to said machinist if the position of said jig is outside the limits set by a selected angle and angle tolerance, and j. means of attaching said jig to said workpiece, whereby said jig can be used to machine said workpiece using said tool, producing various types of bevels including flat bevel, chisel bevel, sabre bevel, compound bevel, and near convex bevel.
 2. The electronic jig as defined in claim 1, wherein a single switch: turns said jig on or off, selects a bevel angle and angle tolerance, selects the next bevel angle in a range of bevel angles, sets the reference angle of said jig, and selects positive or negative bevel angles with respect to said reference angle.
 3. The electronic jig as defined in claim 1, wherein an accelerometer is used to measure angle of said jig with reference to the horizontal or vertical plane.
 4. The electronic jig as defined in claim 1, wherein an inclinometer is used to measure angle of said jig with reference to the horizontal or vertical plane.
 5. The electronic jig as defined in claim 1, wherein said angles and said angle tolerances are programmed into said memory by means of switches.
 6. The electronic jig as defined in claim 1, wherein said angles and said tolerances are selected from said memory by means of a switch or set of switches.
 7. The electronic jig as defined in claim 1, wherein said angles and said angle tolerances are programmed into said memory by means of a wired port.
 8. The electronic jig as defined in claim 1, wherein said angles and said angle tolerances are wirelessly transmitted to said jig and programmed into said memory.
 9. The electronic jig as defined in claim 1, wherein speech recognition is used to understand voice commands from a person to set said angle and said tolerance of said jig.
 10. The electronic jig as defined in claim 1, wherein light emitting components are used to provide feedback to a user to indicate position of said jig with respect to a selected angle.
 11. The electronic jig as defined in claim 1, wherein audio is used to provide feedback to a user to indicate position of said jig with respect to a selected angle.
 12. The electronic jig as defined in claim 1, comprising a temperature sensor to verify that the ambient temperature is within operating specifications of said jig.
 13. The electronic jig as defined in claim 1, wherein a rechargeable battery provides power to said jig.
 14. The electronic jig as defined in claim 1, comprising battery management circuitry to control charging of said rechargeable battery.
 15. The electronic jig as defined in claim 1, wherein a non-rechargeable battery provides power to said jig.
 16. The electronic jig as defined in claim 1, wherein an AC to DC adapter provides power to said jig.
 17. The electronic jig as defined in claim 1, wherein a magnet is used to attach said jig to said workpiece.
 18. The electronic jig as defined in claim 1, wherein a clamp is used to attach said jig to said workpiece. 